Define Type I and Type II error in testing of hypothesis. A psychologist wishes to verify that a certain drug increases the reaction time to given stimulus. The following reaction times (in tenth of seconds) were recorded before and after injection of the drug for each of four subjects:

Subject		1	2	3	4
Reaction Time	Before	7	2	12	12
	After	13	3	18	13

Test at 5% level of significance to determine whether the drug significantly increases the reaction time.